This invention relates generally to load responsive fluid power system or a constant pressure fluid power system using a servo valve in control of a fluid motor driving a load and operated by a variable displacement pump.
In more particular aspects this invention relates to a fluid power system using a variable displacement pump and servo valves in control of loads, in which the flow of pressurized fluid is automatically cut off from the servo valve controlling a negative or aiding load.
In still more particular aspects this invention relates to a system, in which the inlet flow requirements of an actuator controlling a negative or aiding type load are directly supplied from a low pressure source to the actuator, bypassing the servo valve.
Load responsive or constant pressure fluid power and control systems are very desirable for a number of reasons. They permit simultaneous control of multiple loads from one pressure source with high system gain. Normally the servo valves of such a system connect the actuator inlet with the fluid at high pressure level, while controlling a negative load. This results in a very large throttling loss across the controlling orifices of the servo valve, reducing the system efficiency and providing additional parasitic side effects.